My instances are used to scan text to compute the CharacterBlock for a character specified by its index in the text or its proximity to the cursor location.

	scanning
	characterBlockAtPoint:in: characterBlockAtPoint:index:in: characterBlockForIndex:in: characterNotInFont indentationLevel: placeEmbeddedObject:

	stop conditions
	cr crossedX endOfRun paddedSpace setFont setStopConditions tab

	private	top
	buildCharacterBlockIn: handle nullText
	characterPointSetX:
	lastCharacterExtentSetX:
	lastSpaceOrTabExtentSetX:

	scanning	top
	characterBlockAtPoint:in: Answer a CharacterBlock for character in aParagraph at point aPoint. It is assumed that aPoint has been transformed into coordinates appropriate to the text's destination form rectangle and the composition rectangle.
	characterBlockAtPoint:index:in: This method is the Morphic characterBlock finder. It combines MVC's characterBlockAtPoint:, -ForIndex:, and buildCharcterBlock:in:
	characterBlockForIndex:in: Answer a CharacterBlock for character in aParagraph at targetIndex. The coordinates in the CharacterBlock will be appropriate to the intersection of the destination form rectangle and the composition rectangle.
	characterNotInFont See the note in CharacterScanner>>characterNotInFont. This does not handle character selection nicely, i.e., illegal characters are a little tricky to select. Since the end of a run or line is subverted here by actually having the scanner scan a different string in order to manage the illegal character, things are not in an absolutely correct state for the character location code. If this becomes too odious in use, logic will be added to accurately manage the situation.
	indentationLevel: set the number of tabs to put at the beginning of each line
	placeEmbeddedObject: Place the anchoredMorph or return false if it cannot be placed. In any event, advance destX by its width.

	stop conditions	top
	cr Answer a CharacterBlock that specifies the current location of the mouse relative to a carriage return stop condition that has just been encountered. The ParagraphEditor convention is to denote selections by CharacterBlocks, sometimes including the carriage return (cursor is at the end) and sometimes not (cursor is in the middle of the text).
	crossedX Text display has wrapping. The scanner just found a character past the x location of the cursor. We know that the cursor is pointing at a character or before one.
	endOfRun Before arriving at the cursor location, the selection has encountered an end of run. Answer false if the selection continues, true otherwise. Set up indexes for building the appropriate CharacterBlock.
	paddedSpace When the line is justified, the spaces will not be the same as the font's space character. A padding of extra space must be considered in trying to find which character the cursor is pointing at. Answer whether the scanning has crossed the cursor.
	setFont Set the font and other emphasis.
	setStopConditions Set the font and the stop conditions for the current run.
	tab